We devised a sequencing strategy (Additional file 1: Figure S1) to detect footprints generated by transposon remobilization in a set of three T-cell acute lymphoblastic leukemias (T-ALLs) developed in triple-transgenic mice carrying alleles for 1) Cre recombinase expressed from the CD4 promoter, 2) Cre-inducible SB transposase, and 3) a concatemer of T2/Onc2 mutagenic transposons [5]. The gene discussed is CD4; the disease is T-cell acute lymphoblastic leukemia.